Tamper indicating devices for indicating tampering with a screw or the like recessed in a hole are known. One such device comprises a plug which includes a circular cylindrical wall having a transverse wall central between the ends of the cylindrical wall. An annular ridge aligned in the plane of the transverse wall engages an annular groove in the aperture side for retaining the plug in the aperture. This plug requires a tool for breaking and entering the transverse wall and for removing the device. This is undesirable because the plug may be removed and then reinserted into the aperture. The transverse wall, because it is recessed in the aperture is difficult to observe as having been tampered with.